Bottlenose Dolphins Bottlenose Dolphins and Coastal Healthand Coastal Health

Lori Schwacke, Ph.D.Lori Schwacke, Ph.D.NOAA’s Cooperative Center for Marine Animal HealthNOAA’s Cooperative Center for Marine Animal Health

Stress on Coastal EcosystemsStress on Coastal Ecosystems

Loss of species

Altered food webs

↑ algal blooms

Disease/mortality of indicator species

Ecological impacts

↑ fishery closures

↑ health risks

↓ recreational use

↓ aesthetic value

Human impacts

↑ chemical contam.

↑ nutrient

↑ pathogens

↓ suitable habitat

Changes to marine

environment

Increasing human population & coastal

development

Altered land, ↑ impervious surface

↑ pollutants, run-off

Altered waterways

↑ fishing pressure

Time

Bottlenose Dolphin Bottlenose Dolphin ((Tursiops truncatusTursiops truncatus))

U.S. Coastal DistributionU.S. Coastal Distribution

Why Study Dolphin Health?Why Study Dolphin Health?

• Dolphins are sentinels for coastal ecosystems: – Dolphin health reflects availability/quality of prey

& habitat; reflects stressors in environment• Chemical pollutants • Biotoxins• Pathogens

– Increasing reports of dolphin disease and mortality raises concern about deteriorating ocean health

• Environmental stressors affecting dolphins can also affect humans

Chemical ContaminantsChemical Contaminants

• Trace metals• Pharmaceuticals• Perflourinated chemicals

(many consumer products)

• Persistent organic pollutants (POPs)– Chlorinated pesticides

(DDT, chlordanes)– Polychorinated biphenyls

(PCBs)– Brominated flame

retardants

• Wash from land into estuaries via run-off from urban areas, industrial sites or agricultural fields

• Settle into sediments, enter into food chain when they are consumed by bottom-feeding (detrivore) organisms or absorbed by fish gills

Coastal Food WebCoastal Food Web

2° consumers(menhaden, juv.

fishes such as red drum, croaker)

zooplankton

primary producers(phytoplankton)

detrivores (shrimp, mullet)

3° consumers(trout)

Organic debris, benthic microalgae

Biomagnification of Persistent Biomagnification of Persistent Contaminants (Contaminants (e.g.e.g. PCBs) PCBs)

Plankton 0.04 ppm

Small fish 0.2-2 ppm

Largefish

2-8 ppm

Dolphins are top level predators, vulnerable to biomagnification

Dolphins ~10-100 ppm

Organic debris

Bioaccumulation of PCBsBioaccumulation of PCBs

Dolphins are long-lived and have lipid-rich blubber, so vulnerable to bioaccumulation

Figure from Wells et al. 2005, Science of the Total Environment

BiotoxinsBiotoxins

• Biotoxins are produced by certain species of phytoplankton

• Change in environment may cause dramatic increase in phytoplankton (bloom)

• Bloom of toxin-producing algae referred to as Harmful Algal Bloom (HAB)

• Cause fish-kills, intoxicate seafood

Brevetoxin

• Florida “red-tide”• Neurotoxin shellfish poisoning,

respiratory distress

Source: www.whoi.edu

Panhandle Mortality EventsPanhandle Mortality EventsPanhandle Mortality EventsPanhandle Mortality Events

• 152 dolphins stranded, Aug.1999 – May 2000 • 107 dolphins stranded, Mar. – Apr. 2004, no

observed bloom• 93 dolphins stranded, Sep. 2005 – Apr. 2006

• 152 dolphins stranded, Aug.1999 – May 2000 • 107 dolphins stranded, Mar. – Apr. 2004, no

observed bloom• 93 dolphins stranded, Sep. 2005 – Apr. 2006

0 Cells

1-104 Cells

104 -105 Cells

105 -106 Cells

>106 Cells

Dolphin stranding

K. brevis cell count data

Brevetoxin Related Dolphin Brevetoxin Related Dolphin Mortality EventsMortality Events

Brevetoxin Related Dolphin Brevetoxin Related Dolphin Mortality EventsMortality Events

Texas

Mississippi

Louisiana

Alabama

Florida

1999-2000 (152)2004 (107)2005-2006 (93)

2005-2006 (~200)Multi-species

Gulf of Mexico 1946-1947

Why are dolphins in the Florida Why are dolphins in the Florida Panhandle dying?Panhandle dying?

• Unique exposure pathway/vector?

• Secondary stressor?

Sarasota Charleston IRL Beaufort SJB9000

10000

11000

12000

13000

14000

15000

16000

White Blood Cells (per mL)

Mean Mean±0.95 Conf. Interval

*reported in Hall et al. 2007, Fair et al. 2006, Goldstein et al. 2006

* * *Organic debris

Infectious Disease/PathogensInfectious Disease/Pathogens• Viral disease

– Morbillivirus– Encephalopathies (titers to

equine encephalitis)

• Bacterial pathogens– Brucella, Leptospira

• Protozoal parasites– Giardia, Cryptosporidium,

Toxoplasma

• Fungal disease– Lobomycosis, Aspergillosis

Giardia

Leptospira

Brucella

Zoonotic pathogen – infectious agent that can affect both dolphins and humans

SummarySummary

Dolphins are sentinels of coastal health

• Chemical contaminants– Top-level predator, vulnerable to biomagnification– Indicator of bioavailable contaminants – Reflect local trends in contaminant concentrations

• Biotoxins– Warn of biotoxins in the food chain, even when HAB is not

detected; help to identify vectors for biotoxin exposure– Suggest potential for increased susceptibility, interactions

with other stressors• Disease/Pathogens

– Warn of zoonotic pathogens in marine environment

Sampling MethodsSampling Methods

Remote Dart Biopsy• Contaminants, genetics, fatty

acid/stable isotope

Capture-Release• Physical exam, age, telemetry• Health parameters – CBC,

serology, immune suite, urinalysis, biotoxin exposure, etc.

Stranding Response• Cause of death, pathology• Age, reproductive biology, diet

Photo-ID Studies• Distribution, population

abundance, behavior• Mortality/reproductive events Photo: Eric Zolman

The End

Acknowledgments

• NOAA Marine Mammal Health and Stranding Response Program (Panhandle dolphin health assessment project)

• NMFS Southeast Fisheries Science Center, Southeast Marine Mammal Stranding Network (Panhandle dolphin stranding data)

• Florida Fish and Wildlife Research Institute (K. brevis cell count data)

Dolphin Microarray

• Expressed Sequence Tags (ESTs) isolated from dolphin peripheral blood leukocytes

• Focused on stress response and immune function genes